Indicating device



NOV. 29, 1938. s p

INDICATING DEVICE Filed May 28, 1937 INVENTOR 07 70 SIEPKE 6 Z ATTORNEYPatented Nov. 29, 1938 UNITED STATES amass 1' mmoa'rmo DEVICE om Siepke,Berlin-Shaka, Germany, lssignor to Siemens a Halske Aktiengesellsohaft,Siemensstadt, near Berlin, Germany Application May as, 1931, Serial No.145,220

In Germany May-29, 1936 a 4 claims. (01. lie-124.1

In indicator or dial devices known in the prior art, especially in radiobroadcast receivers for setting the apparatus to diiferent stations, theindicator hand or pointer-is guided in its move- 5 ment either by thedial proper or else a glass pane mounted anteriorly thereof, or elsespecial guide strips are disposed on the frame supporting the dial. Adisadvantage in this form of construction is that the replacement of thedials or scales occasionally necessary because of a change in thewave-lengths becomes rather diilicult; in fact, it is often possibleonly by removing portions of the pointer guide mechanism such as theslide or its drive means. It will be understood that 15 this involvesthe risk of a loss of synchronism between the actual position of thepointer and the position of the tuning means. Exact synchronism often ishard to insure because of the fact that the pulleys for the cord driveof the pointer slide are disposed on the frame supporting the scale ordial, and this is rather unstable. For it will be clear that such aframe is liable to become warped or distorted with a resultant relaxingof the cord tension. This causes backlash so that the tuning means driveand the pointer drive will be out of synchronism.

In the arrangement here disclosedwhich is concerned with the guiding ofpointers for station indication in broadcast receiver apparatus and thelike, the said drawbacks have been obviated. This has been obtained byusing the base plate or'mounting plate of the radio receiver for theguidance and supporting of the pointer slide. These base plates ofreceiver apparatus consist mostly of a box punched out of solid sheetsteel and being open in upward direction on which are secured the othercomponent parts of the set as well as the circuit elements. What is hereconcerned is a particularly stable construction part of a broadcastreceiver set which for this reason insures a particularly reliable andinvariable guide for the slide of the station indicator device.

The said guide slide, according to the invention, ccnsistsgssentially ofan angle sheet which is laid against one of the edges of the base plateand which is movable by the agency of a cord drive passing over pulleysfixed on the base. This cord drive is united with the means actuatingthe tuning device, and these also are secured on the base. As a result,all construction elements comprised in the indicator mechanism arearranged on the base plate so that particulariy reliable operation isassured.' It is thus feasible to mount the scale or dial upon a suitinFig. 2,

ably constructed support in a way entirely independent of the indicatormechanism, the said support being unimpeded by parts of the indicator ortuning device so that the dial is replaceable without the pointersetting means being affected or disturbed.

The invention shall now be described in greater detail by reference toFigs. 1 and 2 representing a perspective and cross-section of oneembodiment thereof.

I denotes the chassis or base plate of a broadcast receiver apparatusconsisting of an angular sheet metal piece, on which all constructionparts required for the mounting are attached. For

guiding and holding the slide for thedial pointer 3, which slideconsists of an angular sheet metal piece, there serves the edge 4 of thebase plate. To drive the slide is provided a cordor belt drive 5 whichis passed over pulleys '6 and which is secured by screw I2 to a lug orangle piece I punched out of and bent over the pointer slide 2. Thepointer 3 is attached on a similar lug 8, the latter being cut out ofthe other limb of the angular sheet which constitutes the pointer slide.The driving cord 5 may, as to the rest, be connected with the actuatingmeans I! for the tuning means here shown as a variable condenser I8 byway of gears I1 and shaft I8. By virtue of the particular mode ofarranging the pulleys 6 and the securing cord 5 on the slide 1, itinsures the holding of the slide on the edge 4 of the'base. For the samepurpose, as can be seen especially the securing point of cord 5 on theslide 2 is located higher over the base I and at greater proximity tothe guide edge 4 than the points of contact with pulleys 6. In thismanner, the slide 2 is pressed against the edge 4 of Y the base plate bymeans of a force directed against the base plate in the sense, roughly,of the bisector of the angle between its top por- 40 tion I3 and frontwall It as shown by arrow 9.

The limbs of the slide 2 have been made dissymmetric so that a torquewhich may be set up by the cord 5 as a result of the higher point ofsecuring may be taken up by the larger leg. Between the pointerslide'andthe base I is preferably interposed an insulating layer It,also angular in shape, with a view to facilitating the movement of theslide although this may be omitted if desired. The pointer l is movable60 parallel to a graduated scale It on which the correct setting of thetuning means may be read. Having described my invention, what I claim asnovel and desire to secure by Letters Patent is:

1. Means for indicating the setting of a tuning tuning device andextending in a direction par-.

allel to said flat surface, a slide engaging saidiiat lace and having apointer movable alongside said scale and means connectingssid slide andbelt arranged to cause said slide to press against said fiat race. 1

8. Means for indicating the setting oi a tuning device comprising a liarleaving two flat faces inclined to each other, a belt connected to saidtuning device and extending in tion aim stantially parallel to one ofsaid faces, a graduated scale, a slide formed to engage each 01' saidflat faces and carrying a pointer extending alongside said scale, andcmeans connecting said slide and belt arranged to cause the tension ofsaid belt to cause portions of said slide to lie in contact with saidflat faces.

4. Means for indicating the setting of a tuning device comprising amember having a flat surface, a belt connected to said tuning device andextending parallel to said flat surface, a scale, a slide engaging saidflat surface and having an integrally formed lug oflset from saidsurface, means securing said lug to said belt, said slide having asecond integrally formed lug extending in the direction of said scaleand an indicator on said lug positioned for movement alongside saidscale.

smrm.

